1. Field of the Invention
This invention relates to a decoding equalizer for a sampled value transmission system of high definition television signal, such as MUSE (Multiple Sub-Nyquist Sampling Encoding) system, and to a subrange-type A/D converter used for the decoding equalizer and suited to implement the automatic equalization of the transmission characteristics of the transmission system.
2. Description of the Related Art
The conventional technique for equalizing the transmission path characteristics for the transmission of sampled values produced by offset sampling, such as in the MUSE system, employs standard receivers on the part of the receiver and implements pre-equalization by an encoder on the part of the transmitter so that the receivers have satisfactory reproduction characteristics. However, this technique fails in the achievement of effective pre-equalization if there exists the variability of characteristics among the standard receivers. Another problem is that it necessitates distinct equalization when supplying a signal to different information media such as a BS (broadcasting satellite) system and a 22 GHz ground system.
In the technique of automatic equalization of transmission characteristics for the analog signal transmission of high definition television signal, in which a certain unit impulse signal is inserted as a test signal in the television signal and the characteristics of the transmission path is detected through the subsequent signal processing as disclosed in JP-A-62-172826, it necessitates an A/D converter of 16.2 MHz clock rate for the trunk system and an A/D converter of 32.4 MHz clock rate for the equalizing system.